Down-regulated expression of CXCR1 and CXCR2 on neutrophils in AAV. Levels of CXCR1 (A) and CXCR2 (B) expression on the membrane of neutrophils were measured by flow cytometry and compared between AAV patients in remission (n = 37), AAV patients with active disease (n = 5) and healthy controls (HC, n = 30). Expression levels are presented as MFI corrected for nonspecific binding of isotype control antibodies on neutrophils. Horizontal lines represent medians. *, P < 0.05; **, P < 0.01 ***, P < 0.001. Correlation between CXCR1 and CXCR2 expression (C) on neutrophils was analyzed in patients in remission and with active disease (n = 42, Spearman r = 0.87, P < 0.0001). Dotted line represents the best-fit correlation between CXCR1 and CXCR2 expression. AAV, ANCA-associated vasculitides; ANCA, anti-neutrophil cytoplasmic autoantibody; MFI, mean fluorescence intensity.
Hu et al. Arthritis Research & Therapy 2011 13:R201 doi:10.1186/ar3534